Tiled fiber optic display apparatus

ABSTRACT

A fiber optic display apparatus consists of a plurality of optical fibers which convey a projected image from an input, or first surface, to a display, or second surface, whose area is greater than or equal to that of the first surface, such that any image projected on to the first surface appears enlarged on the second surface. The second surface is comprised of tiles which attach to adjoining tiles by means of flexible tabs and pliable locator rods in such a fashion as to allow the second surface to follow general contours (e.g. concave or convex), while the optical fiber bundles from each tile are collected into a fixture to form the first planar surface. Because of the modular design of the display it can be assembled or disassembled rapidly. A light-diffusing thin sheet or film is applied to the front of each tile of the second surface to effectively increase the numerical aperture of each fiber, thus producing a uniform wide-angle distribution of light from each fiber end and enabling viewing from any angle in front of the display.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] According to Stanford Resources, the Large Screen Display (LSD)market will generate revenues of nearly $4 billion annually by 2002¹.LSD's are typically used in sports stadia and arenas, airports, casinos,and areas of high pedestrian and vehicular traffic. High initial cost,high maintenance costs, installation requirements, and lack ofrobustness have prevented current LSD technologies from more quicklypenetrating the marketplace. Moreover, current LSD technology is limitedto two dimensions (i.e. planar displays), and thus is not as appealingfor new LSD uses such as interactive gaming and immersive environmentssuch as simulators, and integration with architectural structures.

[0003] Fiber optic LSD's offer substantial improvements over currentCRT- and LED-based displays, due to their smaller depth, lighter weight,and elimination of sensitive and expensive electronic components on thesurface of the display. Because the displayed image is generated by adata/video projector, LCD panel, or other equivalent spatial lightmodulator, fiber optic displays are not “resolution bound” as are LEDand CRT displays, which are comprised of a fixed number of RGB pixels onthe display surface. Furthermore, fiber optic LSD's generate neitherheat nor EMI at the display surface.

[0004] Fiber optic displays, however, are not without shortcomings. Oneof the most difficult technical problems of LSD's is the tiling or“shingling” effect due to slight misalignment of the many tiles of whichthe display is comprised. This problem is made worse in fiber opticdisplays, where it is imperative that the fibers terminate on thedisplay at precisely right angles. Without such precise termination, thedisplays appear to lack uniformity in brightness. Since the human visualsystem is very adept at pattern recognition, means must be taken tomitigate the effects of the inter-tile mullions as well as the alignmentand termination of the fiber terminals.

[0005] 2. Description of Related Art

[0006] Several LSD's have been successfully constructed using opticalfiber, and modular displays have been patented. However, because of themethod by which the modules are joined, as well as the lack of asuitable light-shaping diffusion element at the display surface, currentdisplays cannot be contoured.

[0007] The use of smaller tiles is based upon the concept of a“throw-away” display. In other words, if one or more of the tiles aredamaged (e.g., by the impact of a rock or other hard object), they canbe discarded and replaced in the field at minimal cost, withoutdismantling the entire display.

[0008] U.S. Pat. No. 5,892,168 discloses a fiber optic display comprisedof modules which can be adjusted both horizontally and vertically toeliminate the shingling effect. Because of the two-dimensional alignmentmechanism, contoured display surfaces are not feasible with thisinvention. No lensing process is discussed in this patent, a featurethat is essential for contoured displays.

[0009] U.S. Pat. No. 5,818,998 discloses a portable fiber optic LSD. Thespecific embodiment disclosed is not modular, however, and may only becontoured by wrapping it around a contoured object.

[0010] U.S. Pat. No. 5,381,502 discloses a thin or curved displaycomprised of fixed waveguides. Because of its reliance on a scanningdevice, such as a laser, for producing the image, the physicaldimensions and contours of the display are limited. As with thepreceding patent, the display is not modular.

BRIEF SUMMARY OF THE INVENTION

[0011] A novel solution to many of these limitations is the intent ofthe present invention. A contourable fiber optic display apparatuscomprised of modular tiles is disclosed. Despite the possible contoursintroduced by the tiles, the display can be viewed from any anglebecause the luminance from each tile is essentially constant. Theapplication of the light diffusing film obscures each distal fiber endto the point that the human eye cannot detect small tile misalignmentsor mullions. Moreover, the small, lightweight tiles are comprisedentirely of rugged materials and plastic optic fiber, making the displayideal for “harsh” environments. A method of construction is describedwhich allows the display tiles to be semi-permanently joined by flexiblemembers such that the entire LSD can be quickly set up and taken downand can be easily stored in a small place for transport. Such a displayis ideal for military field use for outdoor sporting events and fortrade shows. Permanent displays can be fabricated as well.

BRIEF DESCRIPTION OF DRAWINGS

[0012]FIG. 1 depicts an example of a contoured large screen display.

[0013]FIG. 2 shows three views—front (FIG. 2A); side (cut-away) (FIG.2B); and rear perspective view (FIG. 2C) of a specific embodiment of thepresent invention.

[0014]FIG. 3 shows a rear perspective view of a modular display, showingthe relationship between display tiles and their corresponding inputs.

[0015]FIG. 4 shows five views; a front/back (FIG. 4A); side (FIG. 4B);top (FIG. 4C); and perspective (FIG. 4D) of the design of the fiberbundle collars used in the secondary input matrix. FIG. 4E shows how thefiber bundle collars are attached to each other and to the secondaryinput matrix.

[0016]FIG. 5 shows a block diagram of a complete LSD system, includingprojector, primary and secondary input matrices, and display surface.

[0017]FIG. 6 shows how a piece of material can be cut out to form aninterstitial webbing that can be used to hold display tiles in proximityin a secondary, embodiment of the present invention.

[0018]FIG. 7 shows two views; a top (FIG. 7A); and front perspective(FIG. 7B) of a simple mechanism for quickly connecting optical fiberbundles to display tiles.

DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention is an LSD comprised of a matrix or array oftiles. An exemplary multiply-contoured optical display (1) isillustrated in FIG. 1. Each display consists of a plurality of equallysized tiles (2) adjoined to each other and/or a structural frame (14),in rows and columns, and supported by flexible support rods (16), as maybe viewed in FIG. 3. FIGS. 2A-C are referred to in the followingdescription of the display tiles. Each display tile (2) is assembledfrom parts made of injection-molded plastic, ABS, polycarbonate, orother material appropriate to the environmental conditions in which thedisplay will be deployed. The size of each tile (2) is sufficientlysmall as to allow the radius of curvature required to contour thedisplay in the desired fashion, with smaller tiles (2) allowing asmaller radius (greater curvature). In the specific embodimentdisclosed, the tile size is a 152 mm (6 in.) square, and is comprised ofthree distinct parts: a front piece, a lower cowl and an upper cowl,which are snapped and cemented together after the fibers are insertedinto front the piece, as is standard in the art. The lower and uppercowls, in addition to protecting the fibers, serve as a strain relieffor the fiber bundle (6) The display surface (3) of each tile isperforated by a matrix of concave orifices (4) into which the distalfiber optic ends (5) terminate as may be viewed in FIGS. 2A and 2B. Thehalf-angle of the concave orifices (4) must correspond to the numericalaperture (NA) of the fiber used, such that the cone of light emittedfrom the distal fiber (5) end is not occluded or limited. The fiberoptic strands are collected into a pigtail (6) and are run out of therear of the enclosed tile (2) as shown in FIGS. 2B and 2C. The tileassembly (2) is then filled with expanding foam that serves to bothinsulate and protect the fiber optic strands enveloped therein. On thesurface of the display (3), the fiber terminals (5) are located so thatthey are slightly recessed with respect to the tile surface as isillustrated in FIG. 2B, and are affixed with optical epoxy (e.g., EpoTek301). A light-shaping diffusion film, preferably a holographic diffusionfilm with very high optical transmission and low back-scattering, isthen applied to the display surface (3) of each tile (2). The diffusionfilm is stamped out in such a manner as to leave approximately 30% ofthe tile surface exposed, as illustrated in FIG. 2A. Exposing greater orlesser percentages of the tile with the holographic diffusion filmrelates to the application of the display. For example, indoor displaysrequiring higher pixel densities may have up to 100% of the tile surfacecovered by the holographic film. The base material chosen for the tile(2) must be black, with a matte or stippled surface in order to enhancethe contrast of the display by absorbing ambient light. Alternatively, atranslucent or light-diffusing material may be used for the basematerial. In this case, black, light-absorbing material may be adhered,or silk-screened onto the tile surface to achieve the same effect asillustrated in FIG. 2A. The pitch or spacing between adjacent distalfiber ends (5) is determined by the application, so that displays to beused for proximal viewing will have a higher pixel density than displaysused for viewing at a distance. In the specific embodiment disclosed,the display surface (3) is designed with a matrix of orifices spaced 4mm on center, so that pixel pitches in multiples of 4 mm may be used(e.g., 4 mm, 8 mm, 16 mm, etc). The present invention uses a uniform 8mm on center pitch in both the vertical and horizontal axes The distalfiber ends (5) on the perimeter of the tile are situated half of thepixel pitch, or 4 mm, from the tile edge, so that when several tiles arejoined, the 8 mm pitch is preserved. Each tile (2) is designed with tabs(7) along each of its four sides (edge tiles may have only three tabsand corner tiles only two tabs) as shown in FIG. 2. The tabs, (7)although part of each tile (2), are flexible. Each tile (2) is joined toits four (or three) neighboring tiles by means of a clip (8) which areinserted around and slid over adjacent tabs. Alternatively, severaldifferent clip widths can be made which “force” the adjoining tiles tobe disposed at specific angles.

[0020] Optionally, in a secondary embodiment of the invention, aninterstitial fabric webbing (18) can be used to semi-permanently locateeach tile in proximity to its neighbors as is illustrated in FIG. 6. InFIG. 6, the white areas (17) correspond to the portion of the materialthat is cut out, while the shaded areas (18) correspond to the materialitself. During assembly of the tiles, the front piece of each tile isplaced in front of the material (18), the tabs (17) and locator pinsinserted through the material, and then the two rear cowl pieces aresnapped and cemented onto the front piece as is standard in the art.Such a webbing (18) facilitates a more rapid set-up and tear-down of thedisplay if it is to be used for a temporary application. To further aidin rapid set-up and take-down of the display, an optical coupler (20)may be used where the fiber bundle emerges from the rear of the tile asillustrated in FIGS. 7A and 7B. The optical coupler (20) is attached toeach fiber bundle (6) by means of a collar which has a mating attachmentfixed to the rear of the display tile assembly (2), as may be viewed inFIGS. 3 and 4E. By separating the fiber bundle from the display tile, amatrix of display tiles joined by interstitial webbing (18) may befolded in the same fashion as a map. Efficient optical coupling betweenfiber bundles is achieved by the use of spherical, refractive, ordiffractive microlens arrays such as are known by those skilled in thestate of the art. The fiber bundles may be color coded according tolength, and each bundle may be marked so as to make clear itsorientation.

[0021] The fiber pigtail (6) emerging from the rear of each tile (2) isjacketed so as to protect the fibers from damage. The fiber pigtails arethen collected into a dual input matrix assembly (9) which collectivelyforms the projection surface (10) as shown in FIGS. 3 and 5. The primaryinput matrix assembly (11) is designed in such a way as to allow for twodegrees of freedom, such that a wide range of display sizes and formats(e.g., 3:4 or letterbox) can be accommodated. A secondary input matrix(12) interposed between the display tiles and the primary input matrix(11), limits the motion of the fiber pigtails (6) in the directionlongitudinal to the path of light through the system. This is achievedby affixing a collar (13) at a fixed distance from the polished end ofeach fiber pigtail as show in FIGS. 4A-E. The collars (13) consist ofmale and female tabs that lock together so that all of the collars (13)are coplanar. This aspect of the dual input matrix assembly (9) isessential in that if the fiber pigtail input ends are not coplanar, anyimage projected onto the projection surface (10) will have segments thatare out of focus. The input matrix assembly (9) maybe disposed at anyangle or position relative to the display (1) as constrained by thelocation of the display installation.

[0022] A structural frame (14) may be used in non-permanent applicationsas may be viewed in FIG. 3. Such a frame (14) may be constructed ofextruded or tubular aluminum, plastic, or other suitable material. Eachdisplay tile (2) has a series of vertical and horizontal locatorpassages (15) through which flexible locator rods (16) pass.Alternatively, the locator passages can be formed into the clips (7)that are used to attach adjoining tiles as shown in FIGS. 2B, 2C, and 3.The locator rods (16) can then be attached to the top, bottom, and twosides of the structural frame as illustrated in FIG. 3. The projectiondevice (19) and other electronics are disposed in a separate enclosurefrom the display. After the display is assembled, the projector assemblyis mounted to the input matrix assembly (9), as may be viewed in FIG. 5.

[0023] The fiber optic display screen of the present invention providesa novel method for forming modular contoured or planar displays fromsmall, inexpensive tiles, while still maintaining uniform viewing fromany position or angle. Moreover, the display is rugged and portable.Although specific embodiments are disclosed herein, such embodiments arenot intended to limit the scope of the following claims.

We claim.
 1. A multiply-contoured optical display (1) consisting of aplurality of tiles (2), a dual input matrix assembly (9), a displaysurface (3) and a connecting means between assembly (9) and surface (3)for the purpose of conveying and, in general, enlarging images; astructural frame (14) and matrix of flexible horizontal and verticallocator rods (16) which attach to the tiles (2) to provide stability tothe display (1); a means of projecting spatially modulated light imagesonto the input assembly (9) of said display (1); a means of connectionbetween tiles (2) which allows a multiply-contoured or display ofvirtually any size and/or shape.
 2. The display (1) of claim 1 in whichthe display surface (3) is partially or fully covered by a holographicdiffusion film to act as a light-shaping diffuser for the purpose ofincreasing the effective numerical aperture of the fibers and thuscreating a uniform distribution of light irrespective of viewer position(viewing angle).
 3. The display (1) of claim 1 in which the connectingmeans between input assembly (9) and the display surface (3) iscomprised of fiber optics (5) or other type of optical light guide,which terminate on display surface (3) and are collected into a pigtail(6).
 4. The display (1) of claim 3 in which a mechanism is provided forquickly connecting and disconnecting the fiber pigtails (6) from therear of the display tiles (2) for the purpose of rapid setup andtake-down of the display (1) which involves an optical coupler (20)attached to both tile (2) and pigtail (6).
 5. The display (1) of claim 3in which the distal fiber optic ends (5) are recessed in orifices (4) inthe display surface (3) such that the point of light emitted from eachdistal fiber end (5) is enlarged by the holographic diffusion film onthe display surface (3).
 6. The display (1) of claim 1 in which themeans of projection consist of any type of spatial light modulator (19),whether transmissive or reflective, for the purposes of conveying movingor static images to the input assembly (9).
 7. The display (1) of claim1 in which the dual input assembly (9) consists of two distinctcomponents, a primary (11) for forming a projection surface (10) byorganizing the pigtails (6) in a matrix in horizontal and verticaldirections, and a secondary (12) for fixing the pigtails (6) in such afashion so as to limit their movement in a direction perpendicular tothe plane formed by the projection surface (10) by fixing a collar (13)to said fiber pigtail (6).
 8. The display (1) of claim 1 in which thedual input assembly (9) receives a plurality of pigtails (6) from saiddisplay tiles (2), distributed in a regular array correspondingone-to-one to the arrangement of the display surface tiles (2), suchthat the pigtails (6) and their associated display tiles (2) can bereadily removed and replaced.
 9. The display (1) of claim 1 in which thestructural frame (14) consists of tubular or extruded metal or plasticelements to which are attached pliable horizontal and vertical locatorrods (16) which give structural stability to the surface created byjoining the display tiles (2).
 10. The display (1) of claim 1 in whichthe display tiles (2) are square, rectangular, or, in general, polygonalin shape with flexible tabs (7) on each of four or three sides.
 11. Thedisplay (1) of claim 1 in which the means of connection between tiles(2) are flexible tabs (7) on the side of tile (2) attached to clips (8)which allows for a multiply-contoured or planar display (1) of virtuallyany size and/or shape.
 12. The display (1) of claim 1 in which thedisplay tile (2) is molded or machined in such a fashion as to allow fora range of pixel densities so that the same tile assembly may be usedfor a wide variety of display applications.
 13. The display (1) of claim1 in which the means of connection between multiple display tiles (2)can be an interstitial webbing (18) of plastic, canvas, or other fabricor material, which aids in the rapid set-up, take-down and ease ofstorage and transportation of said display (1).
 14. A multiply-contouredoptical display (1) consisting of a plurality of tiles (2) attached toeach other by tabs (7) with a display surface (3) containing aholographic diffusion film, a dual input assembly (9) connected to saidtiles (2) by fiber optics (5) grouped into pigtails (6) for purpose ofconveying and enlarging images and recessed in orifice (4) in displaysurface (3) such that a point of light from optics (5) is enlarged bydiffusion film on display surface (3); said dual input assembly (9)containing a primary assembly (11) for forming a projection surface (10)by organizing the fiber pigtail (6) in a matrix in horizontal andvertical directions, and a secondary assembly (12) for fixing the fiberpigtail (6) to limit movement in direction perpendicular to plane formedby said projection surface (10) by fixing a collar (13) to said fiberpigtail (6); a structural frame (14) with locator rods (16) attaching totiles (2) to provide stability to display (1); a spatial light modulator(19) for conveying moving or static images to dual input assembly (9).15. A display (1) of claim 14 in which said fiber optics (5) connectedto said tiles (2) may be quickly connected or disconnected by way of anoptical coupler (20).
 16. A multiply-contoured optical display (1)consisting of a plurality of tiles (2) attached to each other by aninterstitial webbing with a display surface (3) containing a holographicdiffusion film, a dual input assembly (9) connected to said tiles (2) byfiber optics (5) grouped into pigtails (6) for purpose of conveying andenlarging images and recessed in orifice (4) in display surface (3) suchthat a point of light from optics (5) is enlarged by diffusion film ondisplay surface (3); said dual input assembly (9) containing a primaryassembly (11) for forming a projection surface (10) by organizing thefiber pigtail (6) in a matrix in horizontal and vertical directions, anda secondary assembly (12) for fixing the fiber pigtail (6) to limitmovement in direction perpendicular to plane formed by said projectionsurface (10) by fixing a collar (13) to said fiber pigtail (6); astructural frame (14) with locator rods (16) attaching to tiles (2) toprovide stability to display (1); a spatial light modulator (19) forconveying moving or static images to dual input assembly (9).
 17. Adisplay (1) of claim 16 in which said fiber optics (5) connected to saidtiles (2) may be quickly connected or disconnected by way of an opticalcoupler (20).